N-H...O and O-H...O hydrogen-bonded supramolecular networks in 4-chloroanilinium, 2-hydroxyanilinium and 3-hydroxyanilinium hydrogen phthalates.

The title salts, 4-chloroanilinium hydrogen phthalate (PCAHP), C6H7ClN+.C8H5O4-, 2-hydroxyanilinium hydrogen phthalate (2HAHP), C6H8NO+.C8H5O4-, and 3-hydroxyanilinium hydrogen phthalate (3HAHP), C6H8NO+.C8H5O4-, all crystallize in the space group P2(1)/c. The asymmetric unit of 2HAHP contains two independent ion pairs. The hydrogen phthalate ions of 2HAHP and 3HAHP show a short intramolecular O-H...O hydrogen bond, with O...O distances ranging from 2.3832 (15) to 2.3860 (14) A. N-H...O and O-H...O hydrogen bonds, together with short C-H...O contacts in PCAHP and 3HAHP, generate extended hydrogen-bond networks. PCAHP forms a two-dimensional supramolecular sheet extending in the (100) plane, whereas 2HAHP has a supramolecular chain running parallel to the [100] direction and 3HAHP has a two-dimensional network extending parallel to the (001) plane.